Method of forming a stress isolating joint on a dump body

ABSTRACT

A method of forming a stress isolating joint on a dump body of on an off-highway rubber-tired haulage vehicle includes providing a first plate having an elongated edge, a top side, and a face, and providing a second plate including an elongated edge. Overlapping the first and second plates to define a widened seam bounded at least in part by the elongated edges of the respective plates, and welding along the elongated edge of the first plate to join the elongated edge of the first plate to an adjacent surface of the second plate. The weld and at least a portion of the second plate disposed along the widened seam cooperate to permit the second plate to apply a resisting load to the face of the first plate in response to the application of a load against an opposing face of the first plate.

RELATED APPLICATIONS

[0001] This application is a division of U.S. application Ser. No.10/151,801 filed May 21, 2002, which claims priority from U.S.Provisional Application Serial No. 60/294,143, filed May 29, 2001.

FIELD OF THE INVENTION

[0002] The present invention relates generally to dump bodies foroff-highway rubber tired haulage vehicles, such as dump trucks. Morespecifically, the present invention relates to a joint isolation systemfor reducing stress in joints between adjacent plates or othercomponents in a dump body.

BACKGROUND OF THE INVENTION

[0003] Dump bodies for off-highway rubber tired haulage vehicles aretypically constructed from a plurality of plates that have been weldedtogether. According to common practice, dump bodies include a floor,sidewalls, and a front wall. Many times a cab protector is attached tothe top edge of the front wall in order to protect the truck cab duringloading operations.

[0004] According to common practice, the plates which form the bulk ofthe load carrying surfaces are joined, such as by welding, to adjacentplates and/or supporting frame members to form the finished dump body.In order to keep the overall weight of the dump body below a desiredlevel, manufacturers often try to use the thinnest plates possible.However, it is known that thin, flat plates are generally not wellsuited for carrying loads perpendicular to their surface.

[0005] Although flat plates can be stiffened somewhat by increasing thethickness of the plates, in dump body applications merely thickening allof the plates is not a desirable option, as such an approach increasesthe weight of the dump body, thus lowering the hauling capacity of thehaulage vehicle. Consequently, thin plates are often welded to otherreinforcing supporting plates disposed at intervals, or are otherwiseconnected to and supported by a network of supporting frame members. Thethin plates serve the goal of keeping the overall weight down, while theother reinforcing members provide the necessary strength. Two examplesof typical prior art construction techniques are shown in FIGS. 8 and 9,both of which experience significant stress along the weld linesindicated as W₁ and W₂ in FIG. 8, and W₃ in FIG. 9.

[0006] Unfortunately, according to conventional construction techniques,such joints often experience problems, such as, by way of example ratherthan limitation, problems with metal fatigue. This metal fatigue isoften most prevalent precisely at the weld lines in the dump body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a perspective view taken from below of a dump bodyassembled in accordance with the teachings of the present invention;

[0008]FIG. 2 is an enlarged fragmentary view in perspective taken fromabove at the circumscribed portion of FIG. 1 and illustrating a jointbetween a thin plate and another plate assembled in accordance with theteachings of a first disclosed embodiment of the present invention;

[0009]FIG. 2A is an enlarged fragmentary view in perspective taken frombelow and from the opposite side of the joint shown in FIG. 2;

[0010]FIG. 3 is a cross-sectional view thereof;

[0011]FIG. 4 is an enlarged fragmentary view in perspective takensimilar to FIG. 2 and illustrating a joint between a thin plate andanother plate in accordance with the teachings of a second disclosedembodiment of the present invention;

[0012]FIG. 4a is an enlarged fragmentary view in perspectiveillustrating a joint between a thin plate and another plate inaccordance with the teachings of an alternative disclosed embodiment ofFIG. 4;

[0013]FIG. 5 is a cross-sectional view taken along line 5-5 of FIG. 4;

[0014]FIG. 6 is an enlarged fragmentary view in perspective taken at thecircumscribed portion of FIG. 1 of a joint assembly in accordance withthe teachings of a third disclosed embodiment of the present invention;

[0015]FIG. 6a is an enlarged fragmentary view in perspective taken atthe circumscribed portion of FIG. 1 of a joint assembly in accordancewith the teachings of a fourth disclosed embodiment of the presentinvention;

[0016]FIG. 6b is an enlarged fragmentary view in perspective taken atthe circumscribed portion of FIG. 1 of a joint assembly in accordancewith the teachings of a fifth disclosed embodiment of the presentinvention;

[0017]FIG. 6c is an enlarged fragmentary view in perspective taken atthe circumscribed portion of FIG. 1 of a joint assembly in accordancewith the teachings of a sixth disclosed embodiment of the presentinvention;

[0018]FIG. 7 is an a cross-sectional view of FIG. 6; and

[0019]FIGS. 8 and 9 illustrate joints between plates assembled inaccordance with the prior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] The following description of the disclosed embodiments are notintended to limit the scope of the invention to the precise form orforms detailed herein. Instead, the following description is intended tobe illustrative of the principles of the invention so that others mayfollow its teachings.

[0021] Referring now to FIG. 1 of the drawings, a dump body assembled inaccordance with the teachings of the present invention is generallyreferred to by the reference numeral 10. It will be understood that thedump body 10, in a preferred environment of use, is for attachment to anoff-highway rubber-tired haulage vehicle (not shown) or other suitablevehicles in which the dump body 10 may prove beneficial. However, theteachings of the invention are not limited to off-highway rubber-tiredhaulage vehicles, to dump bodies, or to any other particular environmentof use.

[0022] The dump body 10 includes a floor 12, a pair of sidewalls 14(only a single sidewall is visible in FIG. 1). The other sidewall maybea mirror image of the one shown. The dump body 10 also includes a frontwall 16. The floor 12, the sidewalls 14, and the front wall 16 cooperateto generally define a payload space 18. The dump body 10 includes arearward portion 20 defining a spillway 22. A pair of brackets 24 areprovided on a bottom surface 26 of the floor 12, which brackets 24enable the dump body 10 to pivot relative to the frame of a dump truck(not shown) about an axis 28 using one or more conventional actuators(not shown) of the type commonly employed in the art.

[0023] The dump body 10 also includes a pair of plates 30, 32 which meetin overlapping relationship to define an elongated seam 34. As shown inFIG. 2, the plate 30 forms a lower portion 36 of the sidewall 14, whilethe plate 32 forms an upper portion of the plate 32. The lower portion36 of the plate 30 and the upper portion 38 of the plate 32 are joinedtogether to form a joint 40 disposed generally along the elongated seam34. Although the joint 40 is shown at an intersection between thesidewall 14 and an upturned portion of the floor 12, it will understoodthat the teachings disclosed herein are equally applicable to otherseams formed at the intersection of other plates used in theconstruction of the dump body 10.

[0024] Referring to FIGS. 2, 2A and 3, the plate 30 includes a pair ofopposed faces 42, 44 and an elongated edge 46, while the plate 32includes a pair of opposed faces 48, 50 and an elongated edge 52. A weld54, which may be, for example and not limitation, a fillet weld, extendsalong the elongated edge 46 of the plate 30, and interconnects theelongated edge 46 of the plate 30 to the face 50 of the plate 32. Itwill be noted that there is no weld securing the elongated edge 52 ofthe plate 32 to the face 42 of the plate 30. The weld 54 may becontinuous along a length of the plates 30, 32. Alternatively, the weld54 may consist of a plurality of discrete weld sections (not shown).

[0025] It will be noted from each of FIGS. 2, 2A and 3 that the plate 30includes a thickness T₁ while the plate 32 includes a thickness T₂. Itwill also be understood that the plates 30, 32 will experience a loadgenerally indicated by the reference arrow L due to the payload carriedin the payload space 18 of the dump body. As shown, the load L isapplied to the face 44 of the plate 30 above the seam 34, and to theface 50 of the plate 32 below the seam 34. Other loads may be appliedsimultaneously along one or more different directions as would be knownto those of skill in the art.

[0026] In operation, the plates 30, 32 may be assembled as shown usingconventional welding techniques and conventional materials. As shown inFIG. 3, stress at the line of intersection (indicated as “A” in FIG. 3)between the edge 52 of the plate 32 and the face 42 of the plate 30 willbe lessened and or minimized, if not eliminated entirely. This may becompared to the prior art construction illustrated in FIG. 8, in whichtwo welds are employed along the seam as indicated by W₁ and W₂. Aswould be evident to those of skill in the art, in the conventionalconstruction, in response to application of the load L stresses would bepresent along both of the welds W₁ and W₂.

[0027] Referring again to FIGS. 2, 2A and 3, in response to theapplication of the load L as shown, the upper portion 38 of the plate 32may bend slightly about the line B (or about a line extending generallyparallel to the line B), due at least in part to the face 42 of theplate 30 pressing against the face 50 of the upper portion 38 of theplate 32. Consequently, the upper portion 38 of the plate 32 applies aresistive, spring-like force as the plate 32 (e.g., the upper portion 38of the plate 32) resists bending about the line B or about a lineextending generally parallel to the line B. Again, this occurs withoutcausing a stress riser at the line A, thus reducing metal fatiguerelated problems along the line A.

[0028] Referring now to FIGS. 4 and 5, a joint 140 shown therein isassembled in accordance with the teachings of a second disclosedembodiment of the present invention. Again, the joint 140 is disposedalong a seam 134 defined by overlapping portions of adjacent plates 130,132, similar to that described above with respect to the firstembodiment, with a lower portion 136 of the plate 130 and an upperportion 138 of the plate 132 overlapping at the seam 134.

[0029] The plate 130 includes a pair of opposed faces 142, 144 and anelongated edge 146, while the plate 132 includes a pair of opposed faces148, 150 and an elongated edge 152. A weld 154, which may be, forexample and not limitation, a fillet weld, extends along the elongatededge 146 of the plate 130, and interconnects the elongated edge 146 ofthe plate 130 to the face 150 of the plate 132. It will be noted thatthere is no weld securing the elongated edge 152 of the plate 132 to theface 142 of the plate 130. In a preferred form, the weld 154 may becontinuous along a length of the plates 130, 132. Alternatively, theweld 154 may consist of a plurality of discrete weld sections (notshown).

[0030] It will be noted from each of FIGS. 4 and 5 that the plate 130includes a thickness T₁ while the plate 32 includes a thickness T₂. Itwill further be noted that in the disclosed embodiment, the thickness T₁is less than the thickness T₂.

[0031] In the embodiment of FIGS. 4 and 5 the elongated edge 152 of theplate 132 includes a chamfered portion 155. A plurality of apertures 157are spaced at intervals along the upper portion 138 of the plate 132,with the apertures 157 being spaced away from the elongated edge 152. Asshown in FIG. 5, each aperture 157 will reveal an exposed portion 156 ofthe face 142 of the plate 130. Each aperture 157 includes a perimeter158, and a weld 160, for example a fillet or other suitable weld may beprovided, such that at least part of the exposed portion 156 of the face142 is secured to the perimeter 158 of the aperture 157, thus furthersecuring the plates 130, 132 together.

[0032] In a preferred form, the weld 160 may extend substantially aroundthe perimeter 158 of the aperture 157. Alternatively, the weld 160 maytake the form of a single weld section within the perimeter 158 or aplurality of discrete weld sections within the perimeter 158.

[0033] In operation, the plates 130, 132 also may be assembled usingconventional welding techniques and conventional materials. As shown inFIG. 5, stress at the line of intersection (indicated as “A” in FIG. 5)between the edge 152 of the plate 132 and the face 142 of the plate 130will be lessened and/or minimized, if not eliminated entirely. Further,in response to the application of the load L as shown, the upper portion138 of the plate 132 may bend slightly about the line B (or about a lineextending generally parallel to the line B), such that the upper portion138 applies a resistive, spring-like force as the plate resists bendingabout the line B. Again, this occurs without causing a stress riser atthe line A, thus reducing metal fatigue related problems along the lineA. This load is further resisted by the weld 160 in the apertures 157.

[0034] As an alternative, the apertures 157 and the weld 160 may bereplaced with a line of mechanical fasteners 162 disposed at intervalsalong the seam 140 as shown in FIG. 4a. In the illustrated embodiment,three mechanical fasteners 162 which may be, for example and notlimitation a set of nut and bolt fasteners, are inserted throughapertures 157 which are extended through both the plates 130 and 132 tohold the two plates 130 and 132 together. The size, location, andspacing of such mechanical fasteners may be readily calculated usingknown engineering principles.

[0035] Referring now to FIGS. 6 and 7, a joint 240 is formed byoverlapping portions of a long plate 230 and a short plate 232. Both ofthe plates 230 and 232 carry a load L, and both plates are supported bya frame member 233 (the plates 230, 232 and the frame member 233 arealso shown in FIG. 1). It will be understood that the joint 240, in apreferred environment of use, forms a part of the dump body 10 (FIG. 1)an off-highway rubber-tired haulage vehicle, as well as in otherapplications in which the details (to be discussed below) of the joint240 may prove beneficial. However, the application of the joint 240 isnot limited to any particular environment of use.

[0036] In the disclosed example, and referring to FIG. 1, the framemember 233 forms part of a generally box-shaped stiffener 211, whichextends generally transverse relative to the pivot axis 28. In thedisclosed example, a pair of such box-shaped stiffeners 211 areprovided, with additional or fewer such stiffeners 211 being provided asneeded. Another such box-shaped stiffener 213 may also be providedextending generally parallel to the axis of rotation 28. Again,additional or fewer stiffeners may be used. In the disclosed example,the stiffener 211 typically includes a the frame member 233 consistingof a generally vertically oriented plate, another vertically orientedplate (mostly obscured in FIG. 1) spaced away from the frame member 233,and an interconnecting bottom plate 235.

[0037] Referring to FIGS. 6 and 7, the plate 230 is long relative to theplate 232 (e.g., the plate 230 extends further to the right and furtherto the left when viewing FIGS. 6 and 7, much further than the plate 232which is visible in outline in FIG. 1 and which, in the disclosedexample, generally surrounds the stiffeners 211 and 213).

[0038] The plate 230 includes faces 242, 244. In the preferredenvironment of use, the face 242 may be referred to as a bottom face,while the face 244 may be referred to as a top face. The plate 232includes faces 248, 250, and includes an elongated edge 252. Again, inthe preferred environment of use and when oriented in the in useposition shown, the face 248 may be referred to as a bottom face, whilethe face 250 may be referred to as a top face 250. Thus, the top face250 of the plate 232 abuts the bottom face 242 of the plate 230. Theplate that forms a portion of the frame member 233 abuts the bottom face248 of the plate 232, and is joined thereto by a weld 253.

[0039] The elongated edge 252 of the plate 232 includes a chamferedportion 255, and a plurality of apertures 257 are spaced at intervalsalong the seam 234, with the apertures 257 being spaced away from theelongated edge 252. The size, location, and spacing of such aperturesmay be readily calculated using known engineering principles.

[0040] As shown in FIG. 7, each aperture 257 will expose a portion 256of the bottom face 242 of the plate 230. Each aperture 257 includes aperimeter 258, and a weld 260, for instance a fillet weld, may beprovided, such that part of the exposed portion 256 of the face 242 issecured to the perimeter 258 of the aperture 257, thus further securingthe plates 230, 232 together. In a preferred form, the weld 260 mayextend substantially around the perimeter 258 of the aperture 257.Alternatively, the weld 260 may take the form of a single weld sectionwithin the perimeter 258 or a plurality of discrete weld sections withinthe perimeter 258. As a further alternative, the apertures 257 and theweld 260 may be replaced with a line of mechanical fasteners (not shown)disposed along the seam 234.

[0041] In operation, the plates 230, 232 also may be assembled usingconventional welding techniques and conventional materials. As shown inFIGS. 6 and 7, stress at the line of intersection A between the edge 252of the plate 232 and the face 242 of the plate 230 will be lessenedand/or minimized, if not eliminated entirely. Further, in response tothe application of the load L as shown, a portion 238 of the plate 232may bend slightly roughly about a line B extending into the plane ofFIG. 7, such that the portion 238 applies a resistive, spring-like forceas the plate 232 resists bending about the line B. Again, this occurswithout causing a stress riser at the line A, thus reducing metalfatigue related problems along the line A. The load L may further beresisted by including the weld 260 in the apertures 257.

[0042] Referring now to FIGS. 6a, 6 b and 6 c, there is illustratedthree alternative embodiments of the joint 240, illustrated as joint 240a, joint 240 b, and joint 240 c.

[0043] Turning to FIG. 6a, there is illustrated a plate 230 a which islong relative to a plate 232 a. The plate 230 a includes faces 242 a,244 a. In the illustrated embodiment, the face 242 a may be referred toas a bottom face, while the face 244 a may be referred to as a top face.The plate 232 a includes faces 248 a, 250 a, 251 a and includes anelongated edge 252 a. Again, in the illustrated environment of use andwhen oriented in the in use position shown, the face 248 a may bereferred to as a bottom face, the face 250 a may be referred to as a topface, and the face 251 a may be referred to as a side face. Thus, thetop face 250 a of the plate 232 a abuts the bottom face 242 a of theplate 230 a. The plate that forms a portion of the frame member 233 aabuts the bottom face 242 a of the plate 230 a, and the plate that formsa portion of the frame member 233 a also abuts the side face 251 a ofthe plate 232 a and is joined thereto by a weld 253 a. A weld 254 a mayalso be provided to join the frame member 233 a to the plate 230 a, 232a.

[0044] As shown in FIG. 6a, each aperture 257 a will expose a portion ofthe bottom face 242 a of the plate 230 a. Each aperture 257 a includes aperimeter 258 a, and a weld 260 a, for instance a fillet weld, may beprovided, such that part of the exposed portion of the face 242 a issecured to the perimeter 258 a of the aperture 257 a, thus furthersecuring the plates 230 a, 232 a together. In a preferred form, the weld260 a may extend substantially around the perimeter 258 a of theaperture 257 a. Alternatively, the weld 260 a may take the form of asingle weld section within the perimeter 258 a or a plurality ofdiscrete weld sections within the perimeter 258 a. As a furtheralternative, the apertures 257 a and the weld 260 a may be replaced witha line of mechanical fasteners (not shown).

[0045] Turning to FIG. 6b, there is illustrated a plate 230 b which islong relative to a plate 232 b. The plate 230 b includes faces 242 b,244 b. In the illustrated embodiment, the face 242 b may be referred toas a bottom face, while the face 244 b may be referred to as a top face.The plate 232 b includes faces 248 b, 250 b, 251 b and includes anelongated edge 252 b. Again, in the illustrated environment of use andwhen oriented in the in use position shown, the face 248 b may bereferred to as a bottom face, the face 250 b may be referred to as a topface, and the face 251 b may be referred to as a side face.Additionally, a portion of the frame member 233 b includes faces 234 b,235 b. The face 234 b may be referred to as the top face, while the face235 b may be referred to as the bottom face. Thus, the top face 250 b ofthe plate 232 b abuts the bottom face 235 b of the frame member 233 b.The frame member 233 b abuts the bottom face 242 b of the plate 230 band is joined thereto by a weld 254 b. The side face 251 b of the plate232 b abuts the bottom face 242 b of the plate 230 b and is joinedthereto by a weld 253 b.

[0046] As shown in FIG. 6b, each aperture 257 b will expose a portion ofthe bottom face 235 b of the supporting member 233 b. Each aperture 257b includes a perimeter 258 b, and a weld 260 b, for instance a filletweld, may be provided, such that part of the exposed portion of the face235 b is secured to the perimeter 258 b of the aperture 257 b, thusfurther securing the supporting member 233 b and the plate 232 btogether. In a preferred form, the weld 260 b may extend substantiallyaround the perimeter 258 b of the aperture 257 b. Alternatively, theweld 260 b may take the form of a single weld section within theperimeter 258 b or a plurality of discrete weld sections within theperimeter 258 b. As a further alternative, the apertures 257 b and theweld 260 b may be replaced with a line of mechanical fasteners (notshown).

[0047] Finally, turning to FIG. 6c, there is illustrated a joint 240 cwhich is constructed in a similar manner as joint 240 b. In theillustrated embodiment, a plate 230 c is long relative to a plate 232 c.The plate 230 c includes faces 242 c, 244 c. In the illustratedembodiment, the face 242 c may be referred to as a bottom face, whilethe face 244 c may be referred to as a top face. The plate 232 cincludes faces 248 c, 250 c, 251 c and includes an elongated edge 252 c.Again, in the illustrated environment of use and when oriented in the inuse position shown, the face 248 c may be referred to as a bottom face,the face 250 c may be referred to as a top face, and the face 251 c maybe referred to as a side face. Additionally, a portion of the framemember 233 c includes faces 234 c, 235 c. The face 234 c may be referredto as the top face, while the face 235 c may be referred to as thebottom face. Additionally, a plate 261 c includes faces 262 c, 264 c.The face 262 c may be referred to as the top face, while the face 264 cmay be referred to as the bottom face. Thus, the top face 250 c of theplate 232 c abuts the bottom face 235 c of the frame member 233 c. Theframe member 233 c abuts the bottom face 242 c of the plate 230 c and isjoined thereto by a weld 254 c. The side face 251 c of the plate 232 cabuts the bottom face 242 c of the plate 230 c and is joined thereto bya weld 253 c. The bottom face 264 c of the plate 261 c abuts the topface 244 c of the plate 230 c and is joined thereto by a weld 270 c.

[0048] Similar to the joint 240 b, as shown in FIG. 6c, each aperture257 c will expose a portion of the bottom face 235 c of the supportingmember 233 c. Each aperture 257 c includes a perimeter 258 c, and a weld260 c, for instance a fillet weld, may be provided, such that part ofthe exposed portion of the face 235 c is secured to the perimeter 258 cof the aperture 257 c, thus further securing the supporting member 233 cand the plate 232 c together. Furthermore, an aperture (hidden and thusnot shown) in the plate 261 c will expose a portion of the top face 244c of the plate 230 c. Each aperture (hidden) includes a perimeter(hidden and thus not shown), and a weld (hidden and thus not shown) suchthat the part of the exposed portion of the face 244 c is secured to theperimeter (not shown) of the aperture (not shown), thus further securingthe plates 261 c, 230 c together.

[0049] In a preferred form, the weld 260 b and the weld (hidden,securing the plate 261 c) may extend substantially around the perimeter258 b of the aperture 257 b as well as the perimeter of the aperture inthe plate 261 c. Alternatively, the welds may take the form of a singleweld section within the perimeters or a plurality of discrete weldsections within the perimeters. As a further alternative, the aperturesand the welds may be replaced with a line of mechanical fasteners (notshown).

[0050] In order to further improve the performance of the dump body 10,the dump body 10 may also be provided with a perimeter reinforcing beamas outlined in copending and commonly assigned U.S. patent applicationSer. No. 10/152,595, Atty. Docket No. 29747/37242A, the entiredisclosure of which is hereby incorporated herein by reference.

[0051] Further, in order to still further improve the performance of thedump body 10, the dump body 10 may also be provided with one or more ofa curved floor, curved sidewalls, a curved front wall, and/or a curvedcab protector, as outlined in copending and commonly assigned U.S.patent application Ser. No. 10/152,889, Atty. Docket No. 29747/36944A,the entire disclosure of which is hereby incorporated herein byreference.

[0052] A joint isolation system according to the teachings of thepresent invention may be used on a variety of fabricated structures suchas, by way of example rather than limitation, a dump body foroff-highway trucks. In accordance with the disclosed example, the jointisolation system may provide a more fatigue resistant joint by isolatingthe highest stresses from the fatigue prone features of the joint, suchas welds or fasteners. Joint isolation in accordance with the disclosedexample may be enabled at least in part by providing a spring-likesupporting member that distributes the highest stresses to a locationwithout fatigue prone features.

[0053] When the dump body is loaded, the payload pushes on the floor,the sidewalls, and the front wall, and these forces are distributedwithin the structure in a manner dependent on the stiffness of themembers as would be known applying known engineering principles. As themain plates (upon which the material is bearing) are made thinner inorder to save weight or for other considerations, the stresses in thesethinner plates become higher, and the fatigue life may be dramaticallyreduced when using conventional fabrication techniques.

[0054] It is known that the fatigue resistance of welded structures istypically much less than that of the parent metal. The lower fatiguelife is usually seen at the toe of the welds and, according toconventional wisdom, is caused by microscopic defects created during thewelding process, stress riser caused by the geometry of the weld, and byvery high residual tensile stresses inherent with the melting andre-solidification during the welding process.

[0055] A joint assembled according to the disclosed example of thepresent invention may allow higher working stresses to be tolerated byisolating the welds from the high stress areas of the structure. Thisisolates the microscopic defects, stress risers, and the residualstresses from the high stress zone, allowing the parent material toprovide the increased fatigue performance.

[0056] The joint isolation system may be implemented in several ways.One embodiment is a splice joint between two thicknesses of plates.According to the first disclosed example, the critical toe of the filletweld is on the thicker member. The material bearing on the inside of thedump body causes the interface between the two plates to bear againstone another with the thick plate acting as a spring supporting thethinner plate. The highest stress location on the thin plate is where itis supported by the thicker plate and there is no weld, therefore thefatigue life is improved.

[0057] According to the second disclosed example (FIGS. 6 and 7), ajoint in the area of a stiffener or reinforcement is provided. In thisexample, the critical toe of the fillet weld is on the plate 232, andthis location is strengthened by both of plates 232 and 230. Thematerial bearing on the inside of the body causes the interface betweenthe two plates to bear against one another with the short plate (232)acting as a spring supporting the long plate (230). The highest stresslocation on the long plate is where it is supported by the short plate(at or near line A) where there is no weld, and therefore the fatiguelife is improved.

[0058] Optional features such as chamfers, holes, holes with perimeterwelds, fasteners, or other means can be used to optimize the behaviorthe joint. The joint could even be made free of all welds by usingfasteners instead.

[0059] A dump body assembled in accordance with the exemplary featuresdisclosed herein will experience a significant weight reduction for thedump body by allowing the main plates to be made thinner. The resultinglighter weight dump body allows the dump truck to operate moreefficiently, use less fuel, or allow more payload to be hauled, whilestill providing an acceptable service life.

[0060] Those skilled in the art will appreciate that, although theteachings of the invention have been illustrated in connection withcertain embodiments, there is no intent to limit the invention to suchembodiments. On the contrary, the intention of this application is tocover all modifications and embodiments fairly falling within the scopeof the appended claims either literally or under the doctrine ofequivalents.

What is claimed:
 1. A method of forming a stress isolating joint on a dump body, comprising the steps of: providing a first plate, the first plate having an elongated edge and a face; providing a second plate, the second plate having an elongated edge; positioning the first and second plates adjacent each other in overlapping relationship to thereby define a widened seam bounded at least in part by the elongated edge of the first plate and the elongated edge of the second plate; and welding the first plate to the second plate only exclusively along the elongated edge of the first plate.
 2. The method of claim 1, including the step of chamfering the elongated edge of the second plate.
 3. The method of claim 1, including the steps of providing at least one aperture through the second plate, the apertures spaced from the elongated edge of the second plate so as to be disposed along the widened seam, the aperture defining an internal edge abutting the face of the first plate, and forming a perimeter weld in the aperture to join at least a portion of the internal edge to the face of the first plate.
 4. A method of forming a stress isolating joint on a dump body, comprising the steps of: providing a first plate, the first plate having an elongated edge and a face; providing a second plate, the second plate having an elongated edge; positioning the first and second plates adjacent each other in overlapping relationship to thereby define a widened seam bounded at least in part by the elongated edge of the first plate and the elongated edge of the second plate; welding the first plate to the second plate only exclusively along the elongated edge of the first plate; providing a third plate, the third plate having an elongated edge; positioning the elongated edge of the third plate perpendicular the widened seam; and welding the elongated edge of the third plate to the second plate.
 5. The method of claim 4, including the step of chamfering the elongated edge of the second plate.
 6. The method of claim 4, including the steps of providing at least one aperture through the second plate, the apertures spaced from the elongated edge of the second plate so as to be disposed along the widened seam, the aperture defining an internal edge abutting the face of the first plate, and forming a perimeter weld in the aperture to join at least a portion of the internal edge to the face of the first plate.
 7. A method of forming a stress isolating joint on a dump body, comprising the steps of: providing a first plate, the first plate having an elongated edge, a first face, and a second face, the first plate further having a first thickness; providing a second plate, the second plate having an elongated edge and a face; providing a third plate, the third plate having a first elongated edge and a second elongated edge; positioning the elongated edge of the second plate adjacent the first elongated edge of the third plate to thereby define a widened elongated edge; positioning the widened elongated edge perpendicular the first face of the first plate; and welding the widened elongated edge to the first face of the first plate.
 8. The method of claim 7, including the step of chamfering the second elongated edge of the third plate.
 9. The method of claim 7, including the steps of providing at least one aperture through the third plate, the apertures spaced from the second elongated edge of the third plate so as to be disposed adjacent the face of the second plate, the aperture defining an internal edge abutting the face of the second plate, and forming a perimeter weld in the aperture to join at least a portion of the internal edge to the face of the second plate.
 10. The method of claim 7, including the steps of providing a fourth plate, the fourth plate having an elongated edge, positioning the fourth plate and second face of the first plate adjacent each other in overlapping relationship to thereby define a widened seam bounded at least in part by the elongated edge of the first plate and the elongated edge of the fourth plate, and welding the fourth plate to the second face of the first plate only exclusively along the elongated edge of the fourth plate.
 11. The method of claim 10, including the step of chamfering the elongated edge of the fourth plate.
 12. The method of claim 10, including the steps of providing at least one aperture through the fourth plate, the apertures spaced from the elongated edge of the fourth plate so as to be disposed along the widened seam, the aperture defining an internal edge abutting the second face of the first plate, and forming a perimeter weld in the aperture to join at least a portion of the internal edge to the second face of the first plate. 